Ganesh Chaturthi falls on the Shukla Chaturthi of Bhadrapada and marks Ganesha's birth. He is Vighnaharta, the remover of obstacles, and also Vighnakarta, the one who places them — the same power, used to test whether an undertaking deserves to proceed. No rite, journey or venture begins without invoking him first.

The puja is performed in madhyahna kaal, the midday window, because Ganesha is held to have been born at noon. The idol is installed for a fixed number of days — one and a half, three, five, seven or ten — and then immersed. The immersion is not a discarding but the point of the whole observance: what is welcomed with full ceremony is also released, and the clay returns to the water it came from.

On this night, custom holds that the moon should not be looked at. Seeing it is said to bring mithya dosha — a false accusation.

Parvati made a boy from the turmeric paste of her own body and set him to guard her door while she bathed. When Shiva returned and the boy — not knowing him — barred the way, Shiva struck off his head. Seeing Parvati's grief, Shiva sent his ganas to bring the head of the first creature they met facing north; it was an elephant, and with it the boy was revived as Gajanana, lord of Shiva's hosts, first to be worshipped before any rite. A second story explains the Chaturthi moon-taboo: the moon laughed at Ganesha's fall from his mount, and was cursed, so seeing it on this night is said to bring a false accusation (mithya dosha).

Ganesh Chaturthi falls in Bhadrapada, still within the monsoon — the reason the idol is traditionally of unbaked river clay and is returned to water at visarjan. The observance is a full ecological cycle: clay is taken from the water, given form and worship for a day and a half to ten days, and dissolved back. The madhyahna (midday) timing follows the tradition that Ganesha was born at noon.

Ganesha is Vighnaharta, remover of obstacles, and equally Vighnakarta, the one who places them — the same power that clears the path can also block it, to test whether the undertaking deserves to proceed. That is why no rite begins without invoking him. And the visarjan is the point, not a discarding: what is welcomed with full ceremony is also released, and the clay returns to the water it came from — devotion held, then let go.

Parvati, wishing to bathe undisturbed, formed a boy from the turmeric paste of her own body and gave him life, telling him to let no one pass. When Shiva returned and was stopped at his own door, he struck the boy's head from his shoulders. Parvati's grief turned to a fury that threatened creation itself, and she would accept nothing but her son restored.

Shiva sent his ganas north with an instruction: bring the head of the first creature they found sleeping with its head to the north. They returned with the head of an elephant. It was placed on the boy, and he rose. Shiva then gave him a boon that Parvati's anger could not have won by force — that he would be worshipped before all other gods, at the beginning of every undertaking, for as long as any rite was performed anywhere.